This is West Ham's most demanding challenge since their return to the Premier League, and one they will relish. Relatively kind opening fixtures have allowed them to settle back in to the top flight impressively, but Arsenal have the guile to ask them questions. The visitors are, though, slightly pressurised after losing some confidence and fluency in defeat to Chelsea. Per Mertesacker's return would be welcome to shore up a defence that has looked vulnerable in his absence, particularly if Andy Carroll is in the mood to cause some damage. Amy Lawrence